1. Field of the Invention
The present invention relates to a method of displaying an effective data capture state in a fingerprint certifying system and a fingerprint certifying device.
2. Description of the Related Art
A xe2x80x9cfingerprint certifying systemxe2x80x9d is based on the fact that individual persons existing in the world have different fingerprint characteristics, and it electrically reads out the fingerprints of respective persons to specify persons which have been registered in advance.
At present, much attention has been paid to the problem of xe2x80x9csecurityxe2x80x9d in various fields. Particularly, most attention has been paid to the fingerprint certifying system among various methods of certifying the subject (i.e., a person in question is certified as a registered person) in an information security field because it is most effective and have highest certainty. According to a general fingerprint certifying system, the fingerprint face of a finger of a person is put on an input sensor for reading and identifying the fingerprint, and if the fingerprint thus read is coincident with the pattern of the fingerprint of a person who has been registered in advance, the person concerned is certified as the person registered (i.e., the subject).
Japanese Laid-open Patent Publication No. Hei-11-197135 discloses a fingerprint image input device and a fingerprint collating device for the fingerprint certifying system as described above. According to this publication, in order to fetch a high-reproducibility fingerprint image through a simple operation, a pair of electrodes are disposed as an element of a pulse oscillating circuit at a finger placing position, and the placing of a finger of a living body at the finger placing position is detected on the basis of the capacitance between the pair of electrodes by variation of the oscillation frequency, whereby an fingerprint image pickup operation is started upon the placing of the finger.
Further, Japanese Laid-open Patent Publication No. Hei-5-189547 discloses a fingerprint collating device. According to the fingerprint collating device of this publication, plural collating window images obtained by segmenting, in the form of windows, a registering fingerprint image which is revised through the directional filtering processing based on the direction data on the rising or sinking lines of the fingerprint which are obtained by dividing the registering fingerprint image into prescribed areas and extracting them respectively is collated with a collating target fingerprint image to certify the person in question. The fingerprint collating device is equipped with a register memory where the direction data extracted from the registering fingerprint image are registered and a revising means which divides the collating target fingerprint image having the same area as the registering fingerprint image into the prescribed areas and carries out the directional filter processing to each corresponding area based on the direction data registered in the register memory to revise the bridges and cracks of the fingerprint included in the collating target fingerprint image, whereby the collating target fingerprint image is revised by using the direction data extracted from the registering fingerprint image and the fingerprint are collated with each other.
Still further, Japanese Laid-open Patent Publication No. Hei-6-28459 discloses a fingerprint collating device for performing a pattern matching between an input fingerprint and a registered fingerprint dictionary to certify a person in question. FIG. 1 shows the construction of the fingerprint collating device disclosed in the above publication.
First, at the time when a dictionary is registered, a fingerprint image signal read out as an image pattern by fingerprint sensor 61 is converted to a digital signal by binary circuit 62, and a feature portion of the fingerprint image is extracted from the fingerprint image signal in feature extraction unit 63. Thereafter, a constant number of feature patterns (main feature patterns) required to certify that a person concerned is the subject are registered in main feature information-storage unit 64, and preliminary auxiliary feature patterns are registered in auxiliary feature information-storage unit 65. Collating unit 66 collates the input fingerprint image with the main feature patterns through the patterning matching at the time when the fingerprint is input. The pattern matching is carried out by judging coincidence or non-coincidence between a pattern read out from a window and dictionary patterns (main feature patterns) stored in the main feature information-storage unit 64 while successively scanning the input fingerprint image with a predetermined size of window. The collation result is stored in order renewal unit 67.
Subsequently, the certification of the person in question is carried out by judging whether the number of coincident patterns (the number of passing feature patterns) obtained through the fingerprint collation result is larger than a predetermined reference value. If the person in question is not certified, the fingerprint collation is carried out again.
If the person in question is certified, the residual auxiliary feature patterns stored in the auxiliary feature information-storage unit 65 are collated with the input fingerprint image, and the collation result is stored in the order renewal unit 67. The using order is renewed by using the pass/fail information of coincidence/non-coincidence stored in the order renewal unit 67. Since the collating operation is carried out on the next input fingerprint image in accordance with the using order, the collating speed is enhanced.
The Japanese Laid-open Patent Publication No. Hei-6-28459 discloses an example in which a timer is provided to the collating unit 66 shown in FIG. 1. The timer starts the counting of clocks from the time when the fingerprint dictionary is registered. When the timer count value reaches a predetermined value, a signal is transmitted from the timer to the order renewal unit 67. When receiving this signal, the order renewal unit 67 deletes unneeded feature patterns stored in the auxiliary feature information-storage unit 65. As a result, only the feature patterns, having high reliability, which are required to certify the person in question remain in the main feature information-storage unit 64 after a predetermined time elapses. Therefore, the collating speed for the subsequent collating operation can be enhanced.
According to the conventional system, however, a fixed amount of data (effective points) must be collected (fingerprint-captured) from a finger put on a fingerprint input sensor to recognize the fingerprint of the finger. Therefore, the conventional technique described above has the following disadvantages.
A first disadvantage resides in that the conventional technique mainly pays its attention to the improvements in the processing time of a fingerprint certifying device, a device having a construction enabling easy certification, etc. in terms of the device side, and thus a person being certified does not know how long it takes to reach the number of points (the number of effective points) enough to certify (recognize) that the person concerned is the subject from the time when the person puts his/her finger to certify/ascertain the fingerprint.
A second disadvantage resides in that the collation result is not informed to the person being certified unless the person concerned has been certified as the subject registered in advance.
An object of the present invention is to display the number of recognized points during the signal processing time period for ascertaining in the fingerprint certification process, thereby keeping the mind of a person being certified free out of anxiety during the ascertaining processing of the subject.
In order to attain the above object, according to an aspect of the present invention, a fingerprint certifying device comprising: a storage unit for storing a registered fingerprint image; a collating unit for collating a collating fingerprint image inputted to a fingerprint sensor with the registered fingerprint image divided into a predetermined number of blocks; a counter for counting the number of effective blocks in which the registered fingerprint image of the predetermined number of blocks is coincident with the collating fingerprint image; and a display unit for displaying the value corresponding to a ratio of the count value of the number of effective blocks to a predetermined block number.
According to a second aspect of the present invention, a method of displaying an effective data capture state when a fingerprint is certified, comprising the steps of storing registered fingerprint images in a storage unit; inputting the pattern of a fingerprint to a fingerprint sensor to read out a collating fingerprint image; collating the collating fingerprint image with the registered fingerprint image read out from said storage unit; counting the number of effective blocks in which the registered fingerprint image divided into the predetermined number of blocks is coincident with the collating fingerprint image; and displaying the ratio of m/n as the effective data and the residual value of 1xe2x88x92(m/n) as the residual data, when the total effective pixel number of the registered fingerprint image is equal to n and the number of the effective pixels corresponding to the effective block number counted up is equal to m wherein m and n represent positive integers.
According to a third aspect of the present invention, a fingerprint certifying device comprising: a storage unit for reading out a registered fingerprint image as a reference and storing the registered fingerprint image on a pixel basis; a fingerprint sensor for reading a finger to be certified as a collating fingerprint image; a collating unit for collating the collating fingerprint image input to said fingerprint sensor with the registered fingerprint image; a counter for counting up pixels which are collated to be coincident between the registered fingerprint image and the collating fingerprint image in said collating unit; and a display unit for displaying a display index in accordance with the count value of said counter, wherein a predetermined number of pixels to the total pixel number of the registered fingerprint image stored on a pixel basis is set as the maximum value of the display index, and the display index is displayed in accordance with the count value of the pixels which are coincident between the registered fingerprint image and the collating fingerprint image.